In the related art, when an electronic apparatus such as a smart card communicates with a reader-writer, the smart card sense an electromagnetism field of the reader-writer (such as a POS machine, an NFC mobile phone) through its coil antenna, and can obtain power supply through the electromagnetism field of the reader-writer. However, the smart card cannot effectively utilize field energy generated by the reader-writer, resulting in power waste of the electromagnetism field of the reader-writer.
Taking a device to be supplied with power being a smart card as an example, as shown in FIG. 1, the smart card includes: a coil and a smart card chip. The coil is connected to the smart card chip through a communication path. When the smart card is connected to a field energy supply device (such as a POS read-writer, an NFC read-writer, an NFC mobile phone) via RF, NFC, or other communication path after entering a field domain (such as being placed in a radio frequency field), the smart card chip may consume field energy through the communication path regardless of whether the smart card chip needs to be in a working state, resulting in power waste. To fully utilize the field energy generated by the field energy supply device, a power supply path can be set to supply power for the smart card. However, if one more power supply coil is provided for the power supply path, the power supply coil may increase difficulties and cost of the power supply path, and also result in an impact on communication between the smart card and the reader-writer through the existing coil. If the power supply path shares the coil with the smart card chip, it is difficult to get the best power supply efficiency as the smart card chip will share a part of power of the coil. Therefore, it is a difficult problem in the related art to increase the power supply efficiency of the power supply path in the case that the power supply path shares the coil with the smart card chip without adding the power supply coil.